Chapter 21: Reinforcement Sensitivity Theory of Personality

Developed by Jeffrey Gray, RST is a neuropsychological theory distinguishing itself from strict behaviorism by focusing on central states of emotion and motivation that mediate the relationship between stimuli and behavioral responses,. The theory evolved as a modification of Hans Eysenck’s model, addressing its limitations by rotating Eysenck's primary dimensions (Extraversion and Neuroticism) to reveal more causally efficient axes: Punishment Sensitivity (Anxiety) and Reward Sensitivity (Impulsivity),which are independent of one another. Gray’s approach used pharmacological evidence, particularly the effects of anxiolytic drugs, to dissect and define fundamental emotional systems,. The post-2000 revision of RST identifies three major systems: the Behavioral Approach System (BAS), which responds to all appetitive stimuli (conditioned and unconditioned), generating emotions like anticipatory pleasure and hope, and is associated with impulsivity and reward-seeking behaviors like addiction,; the Fight-Flight-Freeze System (FFFS), which mediates reactions to all immediate aversive stimuli, generating the emotion of fear, and is linked to phobia and panic,; and the significantly revised Behavioral Inhibition System (BIS), which is triggered primarily by goal conflict (such as approach-avoidance), generating the emotion of anxiety,. The BIS operates in a "control mode" to promote cautious risk assessment, behavioral inhibition, and worry,. The chapter emphasizes the importance of differentiating fear (FFFS-mediated avoidance) from anxiety (BIS-mediated cautious approach to potential danger), reflecting the dimensions of defensive direction and defensive distance (threat perception),. Neuroticism and Extraversion are conceptualized as the emergent products reflecting the combined strengths and balance of these three underlying, biologically based systems. This hierarchical framework helps explain the significant comorbidity observed in psychopathology, linking specific dysfunctions in neural modules to clinical symptoms like generalized anxiety, Obsessional-Compulsive Disorder, and depression,.